1. Field of the Invention
The present invention relates to agricultural sprayers, and, more particularly, to detecting a nozzle blockage in an agricultural sprayer.
2. Description of the Related Art
Agricultural sprayers apply a liquid to a crop or the ground at a specified application rate. The liquid may be in the form of a solution or mixture, with a carrier liquid (such as water) being mixed with one or more active ingredients (such as an herbicide, fertilizer, fungicide and/or a pesticide). The application rate can vary over different parts of a field through the use of precision farming techniques, such as by using GPS data to activate/deactivate boom sections of the sprayer as the sprayer traverses over the field.
Agricultural sprayers may be pulled as an implement or self-propelled, and typically include a tank, a pump, a boom assembly, and a plurality of nozzles carried by the boom assembly at spaced locations. The boom assembly typically includes a pair of wing booms, with each wing boom extending to either side of the sprayer when in an unfolded state. Each wing boom may include multiple boom sections, each with a number of spray nozzles (also sometimes referred to as spray tips). Of course, a self-propelled sprayer also includes an onboard power plant (e.g., diesel engine) providing motive force and other power such as hydraulic power, electrical power, etc.
The spray nozzles on the boom disperse one or more liquids from a tank carried by the sprayer on to a field. Each spray nozzle typically connects to a fluid conduit that is carried by the boom and receives a fluid flow from the tank, typically supplied to the fluid conduit by a pump. The nozzles have an inlet that connects to the fluid conduit and allows the fluid flow through the conduit to flow into the nozzle, which distributes the fluid to the field in a droplet or spray mist form.
During a spray operation, one or more of the nozzles can become clogged due to various reasons such as impurities in the carrier or active ingredient(s) accumulating in the nozzle. The nozzles are typically optimized to reduce application overlap during the spray operation, so even a single clogged nozzle can cause the active ingredient to be improperly applied to the field and leave strips unsprayed which may require a make-up run that generates no revenue but requires additional fuel and labor costs. A make-up run also causes additional ground compaction due to more passes and timing delays in killing the target pest or other operations dependent upon the spray application.
One known way to determine whether a blockage exists within a nozzle is to place a flow rate sensor within the nozzle. The sensor outputs a signal that corresponds to the fluid flow rate within the nozzle, which is compared to a preset value to determine whether a blockage exists in the nozzle. Such arrangements place a relatively large sensor within the fluid flow path in the nozzle, which is usually small, that can disrupt the fluid flow through the nozzle. Depending on the configuration of the nozzles, it can also be difficult to replace the sensors within the nozzle if the sensor fails.
What is needed in the art is a less invasive way to detect nozzle blockages in an agricultural sprayer.